iFixit - Answers With Device "Philips Wake-Up HF3520"

Philips Wake-Up HF3520: Light doesn't stay on when clock reaches actual alarm time

Fri, 26 Dec 2025 00:26:03 -0700

My clock has an issue where the light comes on during the build-up to the alarm, but turns off once the clock hits the actual alarm time (but demo mode works perfectly). It usually would keep the light on for about 90 minutes after the alarm time unless turned off, but it stays off during this time as well. What’s strange is that the clock display is brighter, like the clock knows the alarm is happening, but the actual wake-up light is not on. Sometimes, unplugging the clock for a few minutes and plugging back in can fix this for a few days, but other times that doesn’t work. It’s very frustrating and has made the alarm completely unreliable.

Also, occasionally I get the random clicking sound like it thinks the buttons are being pressed when they’re not, as mentioned in a question by another user. I’m not sure if these are related or not.

As stated, I’ve tried unplugging and plugging back in, I’ve also tried unplugging and holding down the light on/off button for 15 seconds as suggested in another comment. But regardless, the issue eventually comes up again. Any help is appreciated!

⟐ Answer edited December 26, 2025 at 0:26 MST

Philips Wake-Up HF3520: Alarm does not go off

Tue, 09 Jan 2024 15:30:55 -0700

The display turns off when i turn off the room lights at night and alarm doesn't go off in the morning.

⟐ Answered January 09, 2024 at 15:30 MST

Philips Wake-Up HF3520: device "clicking" quickly like proximity sensor feels something

Mon, 01 Sep 2025 01:42:30 -0700

Philips HF3520/01 Wake-Up Light - suddenly starts making never-ending quick “clicking“ sounds, speeding up.. This is normally sound of proximity (touch) sensor.. but there is nothing close to device, and it is clean…. It is unstoppable, only it stops if disconnected from power… After connecting it can work for hours correctly, but problem appears later again…

⟐ Commented September 01, 2025 at 1:42 MST

Philips Wake-Up HF3520: Snooze is not working

Mon, 16 Sep 2024 05:09:22 -0700

Does anyone knows which part is for the snooze? My snooze is no more working.

⟐ Commented September 16, 2024 at 5:09 MST

Philips Wake-Up HF3520: Where to find the reset botton in the wake-up light HF3520?

Fri, 31 Oct 2025 11:31:28 -0700

at some point the lamp stopped working all of a sudden. Should i try to reset it, and in case where, or should the motherboard be replaced?

⟐ Answered October 31, 2025 at 11:31 MST

Philips Wake-Up HF3520: Clicking sound will not stop

Wed, 13 Oct 2021 18:40:22 -0700

Recently my Wake-Up starts randomly making the clicking sound associated with manipulating the controls. Sometimes it gets to the point where it’s just constantly clicking and the only thing I can do to get it to stop is unplug it. Usually when I plug it back in it’s OK for a while, but then starts again. Sometimes it starts immediately and the controls don’t respond. Anyone else have any idea how to remedy this?

Philips Wake-Up HF3520: Hf3520 completely dead but there is voltage

Tue, 16 Sep 2025 04:22:01 -0700

This Hf3520 just stopped working Nothing works but the multimeter shows voltage. I suspect a pcb swap is needed. Does anyone else have an idea?

⟐ Answered September 16, 2025 at 4:22 MST

Philips Wake-Up HF3520: How to fix lamp always on?

Tue, 05 Nov 2024 04:31:07 -0700

I bought a HF3520 second hand, and everything works fine except that whenever the lamp should be totally off it is at full brightness.

For instance, if I press the lamp button the lamp turns to however bright/dim I've set it, but if I press it again it turns to full brightness.

I've tried disconecting it for a while, and reseting it but nothing has worked.

⟐ Commented November 05, 2024 at 4:31 MST

Philips Wake-Up HF3520: Led stays on at full brightness when plugged in and doesn't dim!

Thu, 24 Oct 2024 04:39:54 -0700

The led bulb stays on at full brightness like a lamp as soon as i plug in and doesn't dim at all 😔

All buttons are working fine 😞

⟐ Answered October 24, 2024 at 4:39 MST

Philips Wake-Up HF3520: Power plug connectorkeeps falling out of port

Fri, 03 May 2024 09:17:44 -0700

The power cord outlet only holds one half of the connector so it is loose and keeps falling out. Help! Love the clock hate that it comes unplugged and the alarm won't go off then.

⟐ Commented May 03, 2024 at 9:17 MST

Philips Wake-Up HF3520: How to reset time of day after power outage?

Thu, 24 Sep 2020 06:42:26 -0700

How do I reset time of day after power outage?

⟐ Answered September 24, 2020 at 6:42 MST

Philips Wake-Up HF3520: Way to add custom sounds to alarm?

Fri, 15 May 2026 15:41:54 -0700

Curious if there's a way to add new wake up sounds to the alarm. Even if it overwrites existing sounds, it would be nice to have some other options. Looking at the existing disassembly instructions, there doesn't seem to be an easy way to interface with the software but I still wanted to ask here.

Philips Wake-Up HF3520: Acoustic wake up sound is not synchron with the light.

Thu, 03 Apr 2025 21:56:35 -0700

The sound goes of 10 - 20 minutes after the programmed wakeup time. the light functions well. disconnecting the unit from Power resets it and the light and sound are synced for a few hours.

Philips Wake-Up HF3520: Radio comes on by itself.

Thu, 11 Jul 2024 14:46:51 -0700

I don't use the nature sounds or radio settings and, yet, the radio turns on on its own and it prevents the light alarm from turning off automatically after the max capacity light has been reached. What can be done to stop the radio from doing this? I've tried to chat and with and call Philips but to no avail. I hope you can help. Thanks!

Philips Wake-Up HF3520: Nature sounds do not work

Fri, 21 Jan 2022 21:41:58 -0700

So the speakers still work, as I can still listen to the radio, but the nature sounds have stopped working. Volume is set to max, I have done a factory reset, and running demo mode gives me no nature sound. Help?